Boiling and highest-temperature indicating device



Jan. 13,1925. 1,523,09

R. ZIEGLER BOILING AND HIGHEST TEMPERATURE INDICATTNG DEVICE Fil ed Sept. 3, 1924 Ivvenfar Patented Jan. 13, 1925.

nrren stares ROBERT ZIEGLER, OF GENE, SWITZERLAND.

BOILING AND HIGHEST-TEMPERATURE INDIOATING DEVICE.

Application filed September 3, 1924. Serial No. 735,691.

To all whom it may concern:

Be it known that I, ROBERT ZIEGLER, a citizen of the Republic of Switzerland, residing at Gent, Canton of Genf, Republic of Switzerland, have invented certain new and useful Improvements in Boiling and Highest-Temperature Indicating Devices, of which the following is a specification.

Temperature indicating devices are known in which an evaporable liquid or a gas, enclosed in an air-tight vessel, acts by means of its pressure corresponding to a definite temperature to release a signal.

Heretofore, such a device has always had a special mechanically or electrically operated acoustic signalling means (bell), which made the device cumbersome and liable to derangement.

According to this invention special signalling devices are dispensed with, and instead the vessel has at least one arched wall or membrane adapted, at a definite temperature, to be suddenly flexed or snapped by the pressure within the vessel from a position of curvature on one side of a median plane to a position of curvature on the other side of said plane, thereby giving an audible report.

The extreme simplicity of this device, excluding frictional or jointed parts, ensures reliable indication. Further, the device is very easily cleaned and in the course of cooling the flexible wall or membrane snaps back, under the action of the external atmospheric pressure, automatically and with another report into its original position.

Three constructional forms of the device are illustrated, by way of example, on the accompanying drawing, Fig. 1 being a vertical section of one form, Fig. 2 a similar view of the second form and Figs. 3 and 4 are similar views of the third form.

In Fig. 1, the reference numerals 1, 1 denote two flexible walls or membranes of a flat metal box 2 made in two parts connected air-tight with each other and containing an evaporable liquid indicated at 3, or a gas.

To use the indicator in connection with liquids to be heated, it is placed in the liquid, for instance milk. and floats on its surface. Normally the membranes 1, 1 take up the curved positions indicated by the dotted lines, but the thickness of metal or" the box, the nature and quantity of the liquid or gas contained in the box and the dimensions of the box are such that the membranes suddenly flex or snap outwardly to the positions shown in full lines (by the internal pressure resulting from the evaporation of said liquid or the expansion of said gas) a few seconds before the required boiling point or highest temperature is reached. This sudden flexing of each membrane 1 produces an audible report which serves as a signal. After the first membrane 1 flexes outwards the space for expansion within the box becomes somewhat greater and consequently the flexing of the second membrane 1, and therefore the second signal, occurs somewhat later.

l/Vhen, after the device has been removed from the heated liquid, it is allowed to cool, the internal pressure in the box disappears and the atmospheric pressure restores the membranes 1, 1 to their normal positions with an audible report.

The metal box can be of any shape, for instance it may be cubical in form; and any number of the membranes may be made to produce, either simultaneously or successively, as many detonations as there are flexible walls or membranes.

In the form of the device shown in Fig. 2, the metal box 2 containing the liquid or gas 8 has a flexible wall or membrane 1, a nonflexible bottom 1 and a trumpet or funnelshaped neck or extension 4 to increase the strength of the report.

In the example shown in Figs. 3 and I a device according to the invention works together with an electric switch for the purpose of suddenly switching off the heating current. 5 and 6 are two contacts, of which one, 5, is stationary and the other, 6, is carried by a spring arm 7. This arm is secured between two insulating plates 8 and 9 and is provided with a nipple 10 of insulating material. This nipple only contacts with the membrane 1 of the metal box 2 when the flexible wall 1 projects above its middle or neutral position, so that the contacts 5 and 6 will be suddenly separated. The position of the nipple 10 when the contacts 5 and 6 are in working condition is shown in Fig. 4:. The membrane 1 automatically and suddenly snaps into this position, when the pressure within the box :t'alls below the atmospheric pressure.

WVhat I claim is A device for indicating the temperatures of liquids, comprising a buoyant, air-tight vessel adapted to be placed in the liquid said all when, after c oo lingfthe [piiessure being tested and to float freely on the sur- Within the vessel falls below atmospheric tace thereof in operating position; said'vespressure and the Wall snaps back into its sel containing an evaporable liquid or a gas original position. v 15 l and having a thin, arched top wall which is In testimony whereof I have aflixed my adapted, at a definite temperature, to be signature in presence oftwo Witnesses. suddenly flexed by the pressure Within the vessel from its position of curvature below ROBERT ZIEGLER. a median planeto one above said plane, such Witnesses: sudden flexion itself giving an audiblere- U. BURGI,

port, and asirnilar report being given bythe DORIS PORTMAN. 

